1. Field of the Invention
The present invention relates generally to microscopic inspection methods and apparatus. The present invention relates more particularly to inspection systems for semiconductor manufacturing.
2. Description of the Background Art
A variety of methods have been used to examine microscopic surface structures of semiconductors. These have important applications in the field of semiconductor chip fabrication, where microscopic defects at a surface layer can make the difference between a properly functioning or non-functioning IC. For example, holes or vias in an intermediate insulating layer often provide a physical conduit for an electrical connection between two outer conducting layers. If one of these holes or vias becomes clogged with non-conductive material, this electrical connection between layers will not be established. Automated inspection of the semiconductors is used to ensure a level of quality control in the manufacture of the integrated circuits.